a) Field of the Invention
The present invention is directed to an objective changer for stereomicroscopes, particularly for telescope-type stereomicroscopes.
b) Description of the Related Art
Telescope-type stereomicroscopes are known in principle. In microscopes of this kind, an object arranged in an object plane is imaged by the stereo objective in the principal beam path of the stereomicroscope. The imaging can preferably be carried out at a great distance, e.g., more than 20 m, or in infinity. Telescope system beam paths which are off-axis with respect to the principal beam path and which extend in parallel on the entrance side are removed from the principal beam path following the stereo objective by two telescope systems which generate corresponding magnified or reduced images of the image generated by the objective. Tube lenses are arranged respectively downstream of the telescope systems in the telescope system beam paths and generate intermediate images of the object in corresponding intermediate image planes, these intermediate images being observed through eyepieces. One of the beam paths coming from the telescope system beam paths can be split into an eyepiece beam path and a camera beam path so that images can also be recorded with the stereomicroscope.
Heretofore, a change in magnification was generally carried out in stereomicroscopes by changing the magnification of the telescope systems. Since it is seldom necessary to change the stereo objectives, a stereo objective is held at the stereomicroscope, e.g., by means of a screw thread or a dovetail ring fastening. However, there is an increasing number of stereomicroscope applications in which additional variations in magnification are required by changing the stereo objectives and in which it is desirable to switch quickly between observation conditions. In this connection, changing the conventionally mounted stereo objective is comparatively involved and cannot be carried out quickly.
An autofocusing system for a stereomicroscope is described in DE 101 13 084 A1. The use of an objective changer whose position can be controlled, in particular, e.g., for adjusting an “optimum image section”, is mentioned in connection with the autofocusing system. However, there are no further details given on the type and construction of the objective changer.